Alcohol use disorders, generally known as alcoholism, have taken emotional and financial tolls on American society, cutting across ages, races, ethnicities, and genders, with over 17 million Americans meeting the diagnostic criteria for alcohol abuse or dependence. Clinical data demonstrate alterations in brain structure and function in chronic alcoholics, injuries that may promote the individual s decline to meeting diagnostic criteria for alcohol dependence. Alcohol dependence is characterized by cycles of repeated high alcohol intake and negative emotional consequences of withdrawal that contribute to excessive drinking and susceptibility to relapse. There is a high likelihood that alcohol-dependent individuals will relapse to drinking even after long periods of abstinence, making treatment options challenging. One promising approach for the treatment of relapse to drinking is the identification of mechanisms that contribute to alcohol-induced reductions in brain mass and neurodegeneration. Recent evidence demonstrates that alcohol-induced neurodegeneration is affected by the decreased production of neural and glial progenitors in the adult brain. In the proposed studies, our research will specifically focus on alcohol s effects on the birth and survival of progenitors (glial stem cells and gliogenesis) in the medial prefrontal cortex (mPFC), a brain region implicated in the acute reinforcing effects of alcohol and relapse to alcohol-seeking behavior. Preliminary evidence from our laboratory demonstrated that excessive drinking in a rodent model of alcohol vapor-induced dependence decreased the proliferation and survival of adult-generated mPFC progenitors. Such regulation was not observed in nondependent alcohol self-administering rats, suggesting that the mPFC gliogenic niche is more vulnerable to dysregulation of the homeostatic system during dependence. These results raise a number of fundamental questions about the neuroplastic changes that contribute to alcohol dependence and the neuroplastic mechanisms that underlie the relapse stage of alcoholism. Therefore, this proposal will identify whether reduced gliogenesis in the mPFC could be a vulnerability factor for alcohol dependence and relapse. Animal models of excessive drinking during vapor-induced alcohol dependence and nondependent drinking will be used to (1) determine the cellular mechanisms underlying reduced mPFC plasticity during alcohol dependence (Specific Aim 1), (2) determine impairments in memory and cognitive function dependent on the mPFC during alcohol dependence (Specific Aim 2), and (3) demonstrate a causal relationship between newly born glial progenitors and relapse to alcohol seeking (Specific Aim 3). Immunohistochemical, biochemical, neuroanatomical, and behavioral measures will be used to determine the functional relationships between neocortical gliogenesis and alcohol dependence. The proposed aims will reveal new vulnerability markers for alcohol dependence and impart significant information about targets for medication development.